I'm sure you're even more overwhelmed now than when you started.
First you have to realize that everyone's camping style is different. Some may always camp with electrical hookups others may never camp with electrical hookups.
Does it make a difference for something like a getting the oven or not? YES!
Your trailer is small, an oven gets hot. Summers are hot. So, if you camp during the summer and don't have electricity to use your air conditioning you might not want to use an oven. Someone who always camps with electrical hookups and is able to run their air conditioning is very truthful in saying they always use their oven. But, if you boondock especially without a generator that probably won't apply to you.
Which is a good segue to talk about generators. You said money was tight. A generator is by far you most cost effective means of getting 120 volt power for your trailer while boondocking.
Let's look at having Escape install an inverter.
Solar panel with charge controller - $680
1500 watt Go Power Inverter - $632
So you've spent over $1200 and it can't run your air conditioner.
What can it run? Well, it can charge your laptop! So can a $35 300 watt inverter that plugs into the cigarette plug that comes with your trailer.
Boondocking I think you do need a Solar Panel and charge controller, but, without an large inverter there is no need for a second solar panel. A single 190 watt solar panel is more than enough to keep up with the 12 volt usage of your trailer. LED lights, Maxxair fan, bathroom fan, refrigerator and water heater controls when on propane, water pump, and even running the furnace.
Does the person recommending a $480 second solar panel have an inverter, does he run a microwave on an inverter, does he really need it when just using 12 volt systems? Without knowing the context, it may or may not apply to you.
For the same ~$600 you spent on adding an inverter you can buy a dual fuel 2000 watt inverter generator that can run your air conditioner. And you don't have to buy it today.
The inverter was the one option that I felt, I could install a better system than what Escape offers for less money. That and spray foam and heating pads were the two options that I didn't get, but, plan on adding myself at a later date. I did get a heat pad ready option where ETI runs the wiring for the the heat pads, for later installation.
If you decide not to get an oven, inverter, or microwave. You can opt for a $100 microwave ready option. Escape will move the drawers left, and leave an opening for a microwave under the stove top, and most importantly add an outlet to that cabinet so you can add a microwave at a later date.
If you decide to get an oven, I can see no reason to get an inverter. We have an instapot and love it too. But, before we got the instapot we bought a Presto Pressure Cooker, that works on the propane stove top, and while it requires more attention can do many of the things an instapot can do.
We typically run our generator for a half hour in the morning, while fixing breakfast, and a half hour in the evening when fixing dinner. Typically, those times coincide with campground 'generator' hours too.
Here's what my build sheet ended up being.
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I wasn't on a budget, so I got a lot of options, that you don't need. But, I'm posting it more to show what I didn't get.